// Copyright (C) 2012 Yury Bychenkov (http://bychenkov.com).
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//  - Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//  - Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//  - Neither the name of Yury Bychenkov nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef hashmap_h
#define hashmap_h

#include "common.h"

template <typename Key, typename Value>
class HashMap {
public:
	HashMap(uint8* pool, size_t poolSize, uint pageSize, uint bucketCount);

	#pragma pack(push, 1)
	class Entry {
	public:	
		const Key key;
		Value value;

	private:
		Entry(const Key& key, const Value& value);
		friend class HashMap;
	};
	#pragma pack(pop)

	Entry* put(const Key& key, const Value& value);
	Entry* putIfAbsent(const Key& key, const Value& value);
	Entry* get(const Key& key) const;
	bool remove(const Key& key, Value* valueOut = 0);

private:
	Entry* put(const Key& key, const Value& value, bool ifAbsent);
	uint hash(const Key& key) const;

	#pragma pack(push, 1)
	struct Page {
		uint32 next;
		uint32 count;
		Entry entries[1];
	};
	#pragma pack(pop)

	Page* getPage(uint pageIndex) const;

public:
	class Iterator {
	public:
		bool hasNext() const;
		const Entry* next();
	private:
		Iterator(const HashMap& m);
	private:
		const HashMap& map;
		uint bucketIndex;
		const Page* page;
		uint entryIndex;
		friend class HashMap<Key, Value>;
	};

	Iterator iterator() const;

private:
	uint estimateCapacity(size_t poolSize, uint blockSize);

private:
	uint32* const buckets;
	const uint bucketCount;

	uint8* const bitmap;
	const uint pageSize;
	const uint pageCount;
	const uint pageCapacity;
	uint8* const pages;

};

#include "hashmap.hpp"

#endif // hashmap_h
